We just watched it. Looks like a set, but the designers have definitely been to Tonga Hut (Hollywood.) The area where they were doing Karaoke, with the couch-type seating and stove really shows that. The real place is smaller, with better music.

Initially, I assumed it was a set, because it was such an expansive space. But the level of elaborate detail, and how right they got it, was extraordinary. Notice the wear on the edge of the bar. I began to doubt they'd go to that much trouble (and expense, even) for a couple of scenes in a single episode. So maybe, I thought, they just cleared out most of the seating in an existing place, to make room for the cameras and other equipment. Looking at various pictures, I noticed matching details from the Tonga Hut (I've never been), and thought, that's it!
After looking at more pictures, the Hut doesn't seem to have enough room to clear out that much space. But as was mentioned, they appear to have very specifically mimicked features of the Tonga Hut's decor. That free-standing metal fireplace... that, especially, is what tricked me!

At one point, Sheldon says, "This place is terrific. Why have we never been here before?" I wonder... did they put that much effort into the set, because it will be a recurring hangout, in future episodes? I hope so.
_________________"The rum's the thing..."

The latest episode of Bob's Burgers was titled Pro Tiki/Con Tiki featuring his restaurant going full tiki but most of it looked like it was done by Party City with many painted tikis and a talking pineapple wearing sunglasses, good title though.

Season 1 Episode 19 of "The Rookies" (1972). Episode title "Three Hours to Kill". A couple of shots of Don the Beachcomber's in the background. Show was shot in the LA area, I'm guessing that this is the "UFO" building at Marina Del Rey.